Wang Wubin, Deng Zhixing, Niu Yunbin, Li Yandong, Huang Zhichao, Dong Minqi, Su Qian
National Engineering Research Center of Geological Disaster Prevention Technology in Land Transportation, Southwest Jiaotong University, Chengdu 611731, China.
School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Materials (Basel). 2022 Feb 3;15(3):1180. doi: 10.3390/ma15031180.
This study proposes a new waterproof sealing layer to reduce the impact of water on subgrade beds. The proposed waterproof sealing layer is composed of a polyurethane adhesive (PA) mixture, which aims to control interlaminar deformation and prevent seepage. A variety of laboratory tests were first performed to analyze the attenuation characteristics and mechanical properties of various polyurethane polymer (PP)-improved gravel mixtures under thermohydraulic coupling effects. In addition, a waterproof performance model test of the PP-improved gravel layer was conducted to investigate its waterproof and drainage performance and hydraulic damage mechanism. Finally, the feasibility and effectiveness of the surface structure of the waterproof drainage subgrade bed containing the PA mixture was tested in combination with the treatment project of the Ciyaowan station of the Baoshen heavy-haul railway. According to the experimental and model results, (1) the waterproof layer containing the polyurethane mixture exhibited satisfactory stiffness, elasticity and flexibility. The waterproof layer containing the polyurethane mixture also controlled the deformation between layers, and its mechanical properties remained stable. (2) The waterproof layer with the dense polyurethane mixture performed well in terms of the waterproof aspect, and no infiltration occurred under cyclic load (3). Long-term field monitoring revealed that the effect of the implementation of a PP-improved gravel layer to treat mud pumping was remarkable. The settlement of the PP-improved gravel layer only reached 13.21 mm, and the settlement remained stable in the later stage.
本研究提出了一种新型防水密封层，以减少水对路基床的影响。所提出的防水密封层由聚氨酯胶粘剂（PA）混合物组成，旨在控制层间变形并防止渗漏。首先进行了各种室内试验，以分析在热-水耦合作用下各种聚氨酯聚合物（PP）改良砾石混合料的衰减特性和力学性能。此外，还进行了PP改良砾石层的防水性能模型试验，以研究其防水排水性能和水力破坏机理。最后，结合包神重载铁路磁窑湾站的整治工程，对含PA混合物的防水排水路基床表面结构的可行性和有效性进行了试验。根据试验和模型结果，（1）含聚氨酯混合物的防水层表现出令人满意的刚度、弹性和柔韧性。含聚氨酯混合物的防水层还控制了层间变形，其力学性能保持稳定。（2） 含致密聚氨酯混合物的防水层在防水方面表现良好，在循环荷载作用下无渗透现象。（3） 长期现场监测表明，采用PP改良砾石层处理翻浆冒泥效果显著。PP改良砾石层的沉降仅达到13.21mm，后期沉降保持稳定。
